The Overlooked Compartment of the Critical-zone-complex, Considering the Evolution of Future Geogenic Matter Fluxes: Agricultural Topsoils

In the last decades the application of rock powder or comparable products on soils has increased in agriculture areas leading to additional release of elements and alteration of soil solutions and saturation states of solutes. In the future this practice will continue and areas affected will spread. This trend will likely be fuelled by attempts to optimize carbon dioxide removal by increasing biomass production, soil organic carbon stocks, increase crop production or afforestation. All those efforts demand a certain amount of geogenic nutrients, which need to be replaced. To investigate the release patterns and the downward transport of an array of elements, and to study their fate as well as reaction processes, altered through this practice, a mesocosm experiment was established at Antwerp University. Here, first results are shown focusing on the release and transport of DIC and Mg in the soil downwards after the application of 22 kg m-2 olivine powder with a grain size smaller than 63 μm on average.Elevated DIC and Mg concentrations are detected in case of olivine is applied to mesocosms with wheat and barley, if compared to the mesocsoms without plants, and without olivine.